The present invention relates to another co-pending application entitled xe2x80x9cSelective Removal of a Metal Oxide Dielectricxe2x80x9d which was filed on May 18, 2000 and has a serial number of 09/574,732 and is assigned to the same assignee as the present application.
In the field of semiconductor fabrication, the use of high-k dielectric materials is becoming increasingly common as the desire to increase the device speeds places practical limitations on the thickness of conventional (low-k) dielectric materials such as silicon oxide. Typical high-k dielectric materials for use include metal oxide or metal silicate materials, such as zirconium oxide (ZrO2), zirconium silicate (ZrxSiyOz,), hafnium oxide (HfO2), and hafnium silicate (HfxSiyOz). Unfortunately, it is difficult to incorporate metal oxide dielectrics into processes that use polysilicon gate electrodes. During the conventional deposition of polysilicon on a metal oxide dielectric film, chemical reactions between the source gas used for polysilicon deposition and the metal oxide dielectric can reduce portions of the dielectric thereby adversely affecting the electrical characteristics of the film and degrading device performance or reliability. It would, therefore, be desirable to implement a fabrication process utilizing a metal oxide gate dielectric that is compatible with the subsequent use of conventional polysilicon gates.